Skip to content

Latest commit

 

History

History
89 lines (65 loc) · 3.62 KB

Java - Bits, Bytes and Hexa.md

File metadata and controls

89 lines (65 loc) · 3.62 KB
Raw

Binary Numbers

Interviewcake - Binary Numbers

Bit Manipulation

https://stackoverflow.com/questions/11380062/what-does-value-0xff-do-in-java https://coderanch.com/t/236675/java-programmer-SCJP/certification/xff https://stackoverflow.com/questions/13422259/how-are-integers-internally-represented-at-a-bit-level-in-java/28478572#28478572

https://stackoverflow.com/questions/13422259/how-are-integers-internally-represented-at-a-bit-level-in-java

http://sys.cs.rice.edu/course/comp314/10/p2/javabits.html https://www.topcoder.com/community/competitive-programming/tutorials/a-bit-of-fun-fun-with-bits/ https://www.developer.com/java/data/using-the-java-bit-manipulation-operators.html https://www.tutorialspoint.com/Java-Bitwise-Operators

resolved exercies https://www.hackerearth.com/pt-br/practice/basic-programming/bit-manipulation/basics-of-bit-manipulation/tutorial/ exercises :

Byte Manipulation

Operations on "byte" Data Type Values

Bit Shifting

Left Shifts

When shifting left, the most-significant bit is lost, and a 00 bit is inserted on the other end.

The left shift operator is usually written as "<<".

0010 << 1  →  0100
0010 << 2  →  1000

A single left shift multiplies a binary number by 2:

0010 << 1  →  0100

0010 is 2
0100 is 4

Logical Right Shifts

When shifting right with a logical right shift, the least-significant bit is lost and a 00 is inserted on the other end.

1011 >>> 1  →  0101
1011 >>> 3  →  0001

For positive numbers, a single logical right shift divides a number by 2, throwing out any remainders.

0101 >>> 1  →  0010

0101 is 5
0010 is 2

Arithmetic Right Shifts

When shifting right with an arithmetic right shift, the least-significant bit is lost and the most-significant bit is copied.

Languages handle arithmetic and logical right shifting in different ways. Java provides two right shift operators: >> does an arithmetic right shift and >>> does a logical right shift.

1011 >> 1  →  1101
1011 >> 3  →  1111

0011 >> 1  →  0001
0011 >> 2  →  0000

The first two numbers had a 11 as the most significant bit, so more 11's were inserted during the shift. The last two numbers had a 00 as the most significant bit, so the shift inserted more 00's.

If a number is encoded using two's complement, then an arithmetic right shift preserves the number's sign, while a logical right shift makes the number positive.

// Arithmetic shift
1011 >> 1  →  1101
    1011 is -5
    1101 is -3

// Logical shift
1111 >>> 1  →  0111
    1111 is -1
    0111 is  7